Hi, I had a lovely homebirth for my 4th last year - nos 2 & 3 were short labours and I just felt I didn't want to go to hospital for the 4th. Our hospital is about 15 mins in no traffic but this is London so no traffic is only at night really. During the day it's a minimum of 30 mins and often 45-60 mins.
The midwives were extremely supportive - I was keen but also quite apprehensive and would probably have agreed to going to hospital if they hadn't been so supportive.
They brought round a box of their medical stuff and some jabs to keep in the fridge for placenta delivery (I think?) at about 36 weeks and we chatted through home deliveries, all very low key. I bought a birth pool and we inflated it about 39 weeks and my husband worked out how to fill it. Then we waited.
I went into labour about 11pm, hubbie rang labour ward immediately to warn them and there were 3 midwives there (1 student) within 30 mins and a baby within another 1 1/2 hr! Midwives cleaned up, had a cup of tea, went home - blissful!
However, there was no pressure to go through with a homebirth - had I felt when I went into labour that I wanted to go to hospital, I'd have gone. Had there been any issue with the delivery, me or the baby, the midwife would have called an ambulance and I'd have been at the hospital far faster than we can make it in London traffic.
The support I received was tremendous and until I actually went into labour, I didn't really fully commit myself to a homebirth but once in labour, I knew it was exactly what I wanted.
I guess so many things can change during a pregnancy - you can develop all kinds of things as you go along which would indicate a hospital birth - that questions about delivery tend to be dealt with nearer the time. However you should be able to gauge how keen your midwife team is on home deliveries so you know whether you're likely to get plenty of support should you choose to go that way.
Hope that helps a bit, and congrats on no 3 